Managed care market share and primary treatment for cancer

Objective. Increases in the market share of managed care are associated with decreases in expenditures in the fee-for-service sector. To understand utilization patterns responsible for such savings, we assessed whether increases in managed care market share were related to increases in receipt of equally effective but less costly primary cancer therapies. Data Sources. Cancer registry data linked to Medicare administrative data for a population-based sample of fee-for-service Medicare beneficiaries 66 years and older who were diagnosed with breast or prostate cancer during 1993-1999. Study Design. We used fixed-effects regression models to assess whether county-level increases in the market share of managed care were associated with differences in receipt of cancer therapies that are similar in effectiveness but vary in cost. Principal Findings. Increases in the market share of managed care were not associated with differences in the receipt of mastectomy versus breast-conserving surgery with radiation for women with early stage breast cancer (p = .47) or with the receipt of conservative therapy (versus surgery or radiation therapy) for men with local or regional prostate cancer (p = .30). Conclusions. Increases in the market share of managed care do not appear to influence the receipt of equally effective primary treatments for cancer in the fee-for-service sector.